Been working on this thing for a year need to share with somone.

Posted by Scooter on March 27, 2015 at 9:34pm

3691191911?profile=original3691191927?profile=original     My son and I have been working on this UAV for  year.  We started by designing a foam model and then glide tested it, then started adding to it, servos, power plant, APM 2.5, GPS, rudder yaw damper system. It's been a work in progress.  The plane is a twin boom pusher we settled on this configuration because it seemed functional, looking around this site it looks as though we are not the only ones who came to this conclusion. 

After what's been a year of development we now have a UAV that will autonomously fly nearly any flight path we give it.  We have figured out auto takeoff, and it auto lands also.  The auto landings are a bit firm because of my fear that setting a final waypoint to low may cause a CTAF situation.  So I land firmly, I have some video of the last few auto landings here. https://www.dropbox.com/s/dtg6h1v3a20v8ty/Untitled.avi?dl=0  I'm not sure if anyone has a more experience with putting altitudes at the final waypoint such as 1 or 2m and been successful, if so I'd like to hear about it.  

So we know have this aircraft that can fly a mission, be rerouted by the GCS during  mission, take off, and land itself...    The goal was to build this "thing"  now that we have completed the goal,  what can we do with it?

thanks for looking :-)

 

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  • Developer
    Grant Morphett March 30, 2015 at 5:33pm

    The auto landing code in the Master repository has been improved so there is less flaring at the end and a gentler landing.  It will be available in the next release of APM:Plane. 

    The final waypoint altitude should be 0 otherwise your plane may glide too far or land a bit too heavily.

    Thanks, Grant

    • julian vs > Grant Morphett March 31, 2015 at 10:16am

      The autolanding code really is amazing and works very well.

      There are two things that you need to take into account, first really tune the TECS engine so that the autopilot knows how to manage energy and the glide etc of your airframe.

      second and probably the biggest issue is variance in altitude estimation over time... thats the biggest problem without having a LIDAR etc you really cant repeat a landing with a low altitude flare. 

      If you can land at sub 12 m/s i have had succesful results with sonar, above that speed its not reliable.

      LIDAR is incredible and you will get very consistent results.

  • Marcin Krawczyk March 28, 2015 at 2:41am

    Cool, I like it :-) More info please (basic measurement would be appreciated).

    • Scooter > Marcin Krawczyk March 28, 2015 at 7:18am

      It has a 60" wingspan and a 48" length.  The power plant is a 2200KV 350W motor turning a 6X3.5 prop.  The booms limit prop size to 7".  I am considering changing the motor to something larger.  The batteries I am using  are 2 X 2200mah 20C and it runs the plane reliably for 12min.

      The weight it just under 1800g's gross.  The thrust to weight is low, I get about 50m/min (160 ft)  climb rate. The L/D is around 12m/s with a stall around 7m/s.(25mph/17mph) Flight time is in the area of 12min with a safe reserve.  I'm going to add a third battery to extend the flight time to near 20 min. To add this battery weight reduction is needed and will be accomplished by changing the tail booms to carbon fiber rods. This should reduce total weight by over 200g's.  

      My total power plant / prop efficiency is somewhere around 66%, I'd like to get a bit more out of it.    I think this would require 7" prop and lower KV motor.  Any ideas?  Affordability is a consideration so far I think RDF900 telemetry system was 1/2 the total budget.  A motor prop combination that produces 1000g's of thrust for around the same watt's would be great.

      I do have a large area 4X2X5  of empty space in the fuselage that could be used for something, plus a lot of other smaller area I could cram electronics. 

    • Marcin Krawczyk > Scooter March 28, 2015 at 11:49am

      With this airframe type twin-motor tractor config would be reasonable also.

  • 3D Robotics
    Chris Anderson March 28, 2015 at 2:18am
    The next frontier is better autolandinga, with flaps, reversible motor, Lidar for ground detection and smarter automatic landing pattern planning
    • Marcus Wright > Chris Anderson March 30, 2015 at 7:56pm

      @ Chris  Are the lasers or sonars better for auto landing?  I see both are supported on the Pixhawk.  We have a few RiteWing Z3's that need better auto landing as well.

  • Michael Nauta March 28, 2015 at 12:07am

    Cool Project and decals, (I like the shark face the most). with the introduction of the Drone app kit, and all that space you have up infront, I think there is really very few limiting you from going all out. what are the power specs on it though? AUW etc?

    • Scooter > Michael Nauta March 28, 2015 at 1:58pm

      AUW is around 3.1 pounds.  I think with a few modification I can get it down to 2.6 pounds.  Below I have given the power specs.  I am looking for a new motor prop combination that will provide better efficiency and maybe a few more watts power for a better climb rate.  I'm using a Turnigy D2826/6 2200 KV it will put out about 350 watts, turning a 6X3.5.

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